class Solution {
public:
    bool isVowels(char c) {
        c = tolower(c);
        return c=='a' || c=='e' || c=='i' || c=='o' || c=='u';
    }
    string reverseVowels(string s) {
        int i=0, j=s.length()-1;

        while (i<=j) {
            while(i<=j && !isVowels(s[i])) i++;
            while(i<=j && !isVowels(s[j]))j--;

            if (i<=j) {
                swap(s[i++], s[j--]);
            }
            
        }

        return s;
    }
};